Trammel.



PATENTED FEB. 20, 1906.

No. 813,095. y

J. E'. HOTTMAN.

TRAMMBL.

APPLICATION FILED Amm. 1905.

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jak/Lys UNITED STATES JOHN F. HOTTMAN, OF DUBUQUE, IOWA.

Specification of Letters Patent.

Patented Feb. 2o, 190e.

' Application iled April 7, 1905. Serial No. 254,363.

T0 a/Z whom it may concern:

Be it known that I, JOHN F. HorTMAN, a citizen of the United States, residing at Dubuque, in the county of Dubuque and State of Iowa, have invented a new and useful Improvement in Trammels, of which the following is a specification.

My invention relates to an improved construction of trammel or beam-compass; and it relates particularly to means for adj ustably supporting the headed trammel-point.

' The more important objects of my invention are to provide a simple and compact construction of adjustable trammel-point which shall render the implement comparatively cheap to manufacture and adapt the point to be accurately alined in any position to which it is moved by sliding it on the beam and to be protected against injury from hard usage and rigidly resistant to the torsional strains to which it is subjected in use.

In the accompanying drawings, Figure 1 is a perspective view of my improved trammel on its beam, of which a broken section is shown; Fig. 2, a section taken at the line 2 on Fig. 3 and viewed in the direction of the arrow, and Fig. 3 a section taken at the line 3 on Fig. 2 and viewed in the direction of the arrow.

A is the body of the implement in its preferred form of a socket containing a rectangular opening Al to conform to the cross-sectional shape of the beam B, releasably confined in the socket, through which it passes between upper and lower'bearing plates or washers a and b therein by a set-screw c, workin in a suitable bearing c on the top of the soc iet against the upper plate to distribute the clamping strain of the set-screw uniformly over the areas of the beam covered by the plates. The thickened base d of the socket has formed through it longitudinally a cylindrical chamber e, and the ends of the late are extended downward over the ends of this chamber as ears b and form bearings for set-screwsff, which enter the chamber e, aliningly in contrary directions, for the purpose hereinafter explained. A rectangular slot g is provided longitudinally and cen-l trally through the bottom of the base d to open into the chamber e.

O is the trammeloint, having a rectangular head h of a thickness adapting it to conform to the width of the slot g, which it i'its closely, the head entering the chamber e,

wherein it is adjustably coniined between the screws f andf and being rigidly secured, as by rivets (represented at v in Fig. 3) between bars ii of arc shape in cross-section conforming to the cylindrical shape of the chamber e, the diameter of these bars with the head proper, 7i, rigidly confined between them, conforming to that of the chamber to produce a close fit therein. The chamber e should be drilled in the first instance somewhat smaller than the required diameter and afterward reamed out to the proper size to render it smooth and uniformthroughout lits length, and the slot g may be sawed or milled through the socket-base after the chamber e is completed. The bars 'L i may be formed by sawing or milling lengthwise through a cylindrical steel bar of the diameter of the chamber e, and thereby cutting away equally along opposite sides of its longitudinal center a thickness of the metal corresponding to that of the head h. The point C, including the head h, with its bars i, may be made complete in one piece by drop-forging and milled to adapt the bars to fit the slot g and chamber e.

To assemble the parts, the head h on the bars i isintroduced into the chamber e and slot g at one end of the body A when the plate b is applied in place, and the screwsff are inserted in the ears b to bear against the head and immovably hold the point in any position ofadjustment attained by moving the head lengthwise of its housing-chamber.

The construction of the sliding head includes the bars i, and it affords a large extent ity of the point O and reduces to the minimum wear on the head and consequent inaccuracy in setting the point. Moreover, the construction permits the head to be con tained and housed in the body of the trammel, wherein it is protected by the metal surrounding it against injury from hard usage and enables the point to be rendered rigidly resistant to the torsional strains to which the implement is subjected in use. The adjustingscrews f and f serve to hold and lock the sliding head against any endwise movement or up-and-down displacements in case of wear on the cylindrical head, which is the only part of the implement that shows wear by use, and the snug fit in the slot g of that portion of theJ head which passes through it prel vents any turning movement of the point on i the longitudinal axis of the head.

of bearing-surface, which increases the rigid-- IOO` IIO

With my improved construction of trammel it is not necessary in the use of the implement that the beam B present a perfectly straight edge.

What I claim as new, and desire to secure by Letters Patent, is-

l. In a trammel, the combination of the body, adapted to be adjustably supported on the beam, provided with a chamber and a slot communicating therewith, a trammelpoint having a head passing through said slot into said chamber and snugly 'litting in the latter, set screw bearings at opposite ends of said chamber, and set-screws in said bearings between which said head is adjustably confined.

2. In a trammel, the combination of the body, adapted to be adjustably supported on the beam, having a cylindrical chamber and a rectangular slot communicating therewith, a trammel-point having a head passing through said slot into said chamber and provided therein with side bars rendering the head of cylindrical shape, `and set-screws Working in bearings on said body and between'which said head is adjustably coniined.

3. In a trammel, the combination of a socket through which the beam passes, pro- I vided with means for fastening it in adjusted position on the beam, and having a cylindrical chamber in its base with a rectangular slot extending through said base into, the chamber, a trammel-point having ahead passing through said slot into said chamber and of cylindrical shape in the latter, and setscrews entering said chamber and between which said head is adjustably confined.

4. A trammel comprising, in combination, a socket containing upper and lower bearingplates and through which the beam passes between said plates, a set-screw on the socket working against the upper plate, a cylindrical chamber in the base of the socket and a rectangular slot extending through said base into the chamber, a trammel-point having a head passing through said slot into the chamber and provided therein with side bars from the lower bearing-plate over the ends of said chamber, and set-screws, between which said head is adjustably confined, working in said ears.

JOHN F. HOTTMAN.

In presence of- Louis C. KOLFENBAGH, ROBERT E. HAGERTY.

rendering the head cylindrical, ears extending 

